All the special relativistic effects can be encapsulated in a few formulae which relate the space-and-time coordinates measured by one observer to the corresponding coordinates measured by another observer, moving relative to the first.
Note that the equation for position in the moving coordinate system has both position and time from the stationary coordinate system. That's not unusual: in everyday life we often use time to describe space.
It's about two hours to Niagara Falls from Rochester.
The unusual feature of these equations appears in the last one: the equation for time in the moving coordinate system includes both time and space from the stationary system. We don't encounter that very often in our ordinary lives. In other words, you don't often hear someone say,
Boy, that movie must have lasted for thirty yards!
It is this mixing of the time and space coordinates that gives rise to the term spacetime, which you may have heard in discussions of relativity.
Copyright © Michael Richmond. This work is licensed under a Creative Commons License.